验证Angular 2复选框列表

发布时间：2020-12-17 17:44:25 所属栏目：安全来源：网络整理

导读：我有一个业务单位列表,在注册表单上呈现为复选框以及文本框字段并进行验证. label for="inputFirstName" class="sr-only"First name/labelinput type="text" formControlName="firstName" class="form-control" placeholder="First name" div class="checkbo

我有一个业务单位列表,在注册表单上呈现为复选框以及文本框字段并进行验证.

<label for="inputFirstName" class="sr-only">First name</label>
<input type="text" formControlName="firstName" class="form-control" placeholder="First name">

 <div class="checkbox" *ngFor="let bu of businessUnits">
        <label><input type="checkbox" #instance value="{{bu.BuName}}" (click)="getCheckBoxValue(instance.checked,bu.BuName)">{{bu.BuName}}</label>
    </div>

从数据库表中检索业务单位列表,并在表单加载时呈现

businessUnits: BusinessUnit[] = [];

在构造函数中,我正在验证这样的电子邮件

"firstName": new FormControl('',[Validators.required]),

})

如何验证在页面加载时动态加载的checbox列表中至少有一个复选框？

谢谢

解决方法

让我们试试这个演示： https://stackblitz.com/edit/angular-custom-form-validation?file=app/app.component.ts

第二个参数将接受验证器功能,就这样通过

this.fg = this.fb.group({
  firstName: ['',[Validators.required]],bUnits: this.fb.array(
    this.businessUnits.map(() => this.fb.control('')),CustomValidators.multipleCheckboxRequireOne
  )
});

AppComponent

import { Component,OnInit } from '@angular/core';
import { FormGroup,FormArray,FormBuilder,Validators } from '@angular/forms'

import { CustomValidators } from './custom.validators';

@Component({
  selector: 'app-root',template: `
    <form (ngSubmit)="onSubmit()" novalidate [formGroup]="fg">
      <div><input type="text" formControlName="firstName" class="form-control" placeholder="First name"></div>
      <div formArrayName="bUnits">
        <div *ngFor="let unit of fg.controls.bUnits.controls; let i = index;">
          <p>Unit {{ i + 1 }}</p>
          <div>
            <label>
              <input type="checkbox" [formControlName]="i" [value]="businessUnits[i].value">
              {{businessUnits[i].name}}
            </label>
          </div>
        </div>
      </div>

      <button type="submit">Submit</button>
      <p>Status {{ fg.valid }}</p>
    </form>
  `
})
export class AppComponent implements OnInit {
  fg: FormGroup;
  businessUnits: any[] = [];

  constructor(private fb: FormBuilder) {}

  ngOnInit() {
    // do some stub to grab data
    this.businessUnits = [
      {name: 'BU 1',value: "1"},{name: 'BU 2',value: "2"},{name: 'BU 3',value: "3"}
    ];
    this.fg = this.fb.group({
      firstName: ['',bUnits: this.fb.array(
        this.businessUnits.map(() => this.fb.control('')),CustomValidators.multipleCheckboxRequireOne
      )
    });

  }

  onSubmit() {
    console.log(this.fg);
  }
}

CustomValidators

import { FormArray } from '@angular/forms';

export class CustomValidators {
  static multipleCheckboxRequireOne(fa: FormArray) {
    let valid = false;

    for (let x = 0; x < fa.length; ++x) {
      if (fa.at(x).value) {
        valid = true;
        break;
      }
    }
    return valid ? null : {
      multipleCheckboxRequireOne: true
    };
  }
}

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